WASHINGTON — Unable to prevent Barack Obama from becoming president, rigid followers of the Constitution have turned their attention to another young, charismatic politician many think could one day occupy the White House.

The birthers are calling for U.S. Sen Marco Rubio, the budding Republican star from Florida.

"It's nothing to do with him personally. But you can't change the rules because you like a certain person. Then you have no rules," said New Jersey lawyer Mario Apuzzo.

Forget about Photoshopped birth certificates; the activists are not challenging whether Rubio was born in Miami. Rather, they say Rubio is ineligible under Article 2 of the Constitution which says "no person except a natural born citizen ... shall be eligible to the Office of President."

The rub is that "natural born citizen" was never defined.

The birthers rely on writings at the time of the formation of the republic and references in court cases since then to contend that "natural born" means a person born to U.S. citizens. Rubio was born in 1971 at Cedars of Lebanon Hospital, his office said, but his parents did not become citizens until 1975. (story here)